2025/05/02 by Bargieła, Piotr
Physics and Astronomy · #530 Physics #Black Holes and Theoretical Physics #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · doi:10.5167/uzh-281097
openalex publication_date 2025/05/02 · openalex created_date 2025/12/11 · openalex updated_date 2026/07/28
We consider multi-loop scattering amplitudes in dimensionally regularized Quantum Field Theory. We present an algorithmic way of reconstructing them from their cuts. We rely on combining modern computational methods with formal developments in discontinuities and dispersion relations. Our approach extends Generalized Unitarity by constraining not only the integrand of the amplitude but also its full integrated form. We validated our method by reproducing the four-gluon amplitude in two-loop massless Quantum Chromodynamics. Moreover, since our approach improves the performance of the calculation, we provide a new result for the four-loop four-point massless planar ladder Feynman integral. It is expressed in terms of Harmonic Polylogarithms with letters 0 and 1.